a. Field of the Invention
The present invention relates generally to a method and system for constructing an electrophysiology map. More particularly, the present invention relates to a computer-implemented method and system for mapping electrophysiological information onto a multi-dimensional geometric model of an anatomic structure, such as, for example, the heart or a particular portion thereof.
b. Background Art
For many years, computer-implemented methods and systems have been used to generate or construct multi-dimensional surface models of anatomic structures, and/or to map electrophysiological (EP) information corresponding to anatomic structures onto multi-dimensional surface models thereof. More specifically, a variety of methods or techniques have been used to construct surface models of structures of the heart (i.e., cardiac structures), and/or to map EP information relating to the cardiac structures onto surface models thereof, thereby forming EP maps of the cardiac structure.
For example, in accordance with one conventional EP mapping technique, and in general terms, a multi-dimensional model of a cardiac structure is obtained comprising position information for a plurality of location data points on the surface of the cardiac structure. An EP map comprising position information for a plurality of measurement points and EP measurements made at each measurement point is also obtained. Once the model and the map are obtained, a location data point of the model is chosen, and the two measurement points of the EP map that are closest to the chosen location data point are determined. The Delaunay triangulation technique is then used to define a Delaunay edge between the two measurement points determined to be the closest measurement points to the chosen location data point. The aforedescribed process is then repeated for each of the location data points in the model, resulting in the definition of a plurality of Delaunay edges.
Once the process is complete for each location data point, the Delaunay edges are connected to form a plurality of triangles. One of the location data points from the model is then selected, and the triangle formed of Delaunay edges that surrounds the selected location data point is identified. A value or level of the EP parameter being mapped is then assigned to the location data point based on interpolation using the EP measurements measured at each of the vertices (i.e., measurement points) of the identified triangle. This process is then repeated for each of the location data points until each location data point has a value of the EP parameter assigned thereto.
Once a location data point has an EP parameter value or level assigned thereto, a color or some other visual indicator is assigned to the location data point based on the relative magnitude of the EP parameter value assigned to the location data point. The model is then presented using the color(s) or other visual indicator(s) assigned to the location data point(s).
Techniques such as that described above, however, are not without their disadvantages. For example, in the above described technique, because each location data point of the model is evaluated and a Delaunay edge defined for each, then a plurality of triangles are formed from the plurality of edges, and then an EP value assigned to the location data point based on an interpolation of EP measurements of three measurement points, all before a visual indicator is assigned, the mapping process is very time intensive. Further, the mapping process is unduly complex and, as a result, may utilize an undesirable amount of computing resources.
Accordingly, there is a need for a method and system for constructing or generating an electrophysiology map corresponding to an anatomic structure that will minimize and/or eliminate one or more of the above-identified deficiencies.